[HELP] Bluetooth lag

Dear all,
I have a weird issue with the bluetooth since Kitkat upgrade. I have tried stock KK D80220D, Pardus HD 7.0 and Cm11 (based on D80220B) and got the same issue.
I am using bluetooth for listening to music via a bluetooth speaker and I have no issue with both an iPhone 4s or an Android JB tablet.

To come to the point, I have 2 issues:
- Bluetooth play sound with a delay of 1/2 to 1 sec according to the app (youtube, music saved in my SD), but it is never synchronised!!
- with the Youtube app, if I am connected in bluetooth and loading HD videos over wifi, the videos goes into buffer and I have to wait (looks like it try to download videos using a mix of bluetooth/wifi). If I use LTE(4G) or I switch off bluetooth the issue disappears.

I consider this inacceptable for such a premium device and I am sure this is a tweak/coding issue.

Before moving back to JB I would really like to find a fix (modem/baseband upgrade/downgrade) or to know if you have the same issue.

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